Hi
You can delete all but the last point by going to Programs>Accessories>System Tools>Disk Cleanup - then clicking on the 'More Options' tab and then System Restore>Clean up...
If you want to delete all of the SR points - right click on My Computer, select Properties and then the System Restore tab. Select 'Turn off system restore on all drives' - then reboot your PC. After rebooting, re-enable SR and then reboot. After that second reboot SR will have created one new point for you.
Will